1. Field of the Invention
The present invention relates to the field of a mobile radio communication system, such as a portable radio telephone system or a vehicle telephone system. The present invention also relates to a mobile radio communication network in said mobile radio communication system and a mobile radio station in said mobile radio communication system.
2. Description of the Related Art
Generally, a mobile radio communication system has an intermittent power-supply system. The intermittent supply system is used for extending a using time of a mobile radio station. The mobile radio station has a battery as a power supply unit. Each of mobile radio stations in said system receives a signal intermittently at an interrupt time interval. An alternate expression for interrupt time interval is interrupt time cycle. In said system, each of mobile radio stations receives radio frequency signals only in the period of its control channel. Receiving the signals only in the period of its control channel reduces the consumption of the electric power.
For example, a cellular radio telecommunication system generally has two or more radio areas, each of said radio areas is controlled by a base station. The base station controls a plurality of mobile radio stations, said each mobile radio stations are located in each said radio areas. Said mobile radio stations are connected to the base stations over radio channels.
FIG. 10 shows a frame of one of said radio channels.
The frame consists of a frame synchronization channel F and eight paging channels P1 to P8. In other words, the system which uses the radio channel shown in FIG. 10 has 8 base stations BS1 to BS8. The system has 8 radio areas G1 to G8. Accordingly, the base station BSi controls mobile radio stations which are located in the radio area Gi (i=1 to 8).
Said system uses said frame synchronization channel F to transmit a frame synchronous signal, a outgoing call control channel number, and other information in said system. Said frame synchronous signal makes a mobile radio station set a frame synchronization.
In said system, the base station BSi (i=1 to 8) uses said paging channel Pi (i=1 to 8) to transmit an incoming call to the called mobile radio station which is located in the radio area the base station BSi (i=1 to 8) controls.
Accordingly, each of mobile radio stations which is controlled by a base station BSi receives radio frequency signals only in the period of the frame synchronization channel F and its paging channel Pi.
For example, as shown in FIG. 10, each of mobile radio stations which is located in the radio area G1 supplies a electric power to a part which requires a electric power and receives radio frequency signals only in the period of the frame synchronization channel F and the paging channel P1. In other period, the mobile radio station stops supplying a electric power to the part which requires a electric power in the mobile radio station, and stops receiving said signals.
As same as above, each of mobile radio stations which is located in radio area Gi supplies a electric power to a part which requires electric power only in the receiving period of the frame synchronization channel F and the paging channel Pi, in other period, said mobile radio station stops supplying the electric power.
As mentioned above, as each of mobile radio stations in said system receives a signal intermittently at an interrupt time interval. Receiving a signal intermittently at an interrupt time interval saves a 7/9 electric power, compared as always receiving radio frequency signals. In above system, increasing a number of the radio area reduces further electric power supplied to a mobile radio station. However, it also extends an interrupt time interval.
As a bad result for extending an interrupt time interval, it costs a long time for a mobile radio station to receive a signal transmitted from a mobile radio communication network in said system.
In the system, furthermore, the mobile radio station never selects an interrupt time interval. The mobile radio station has to receive a signal at a fixed interrupt time interval. Accordingly, the mobile radio station receives useless signal because of receiving the signal at the fixed interrupt time interval.
Furthermore, when the control station in said system receives an incoming call addressed to the mobile radio station, the incoming call indicating that a calling station requests a simplex communication (for example, voicemail, facsimile, other data communication), the mobile radio station has to always receive data in accordance with said simplex communication because that the mobile radio communication network doesn't store the data. An alternate expression for simplex communication is one-way communication.